Herrera María Dolores, Bueno Rosario, De Sotomayor María Alvarez, Pérez-Guerrero Concepción, Vázquez Carmen M, Marhuenda Elisa
Department of Pharmacology, Faculty of Pharmacy, University of Seville, C/ Profesor García González s/n, 41012-Seville, Spain.
J Pharm Pharmacol. 2002 Oct;54(10):1423-7. doi: 10.1211/002235702760345536.
The aim of this work was to investigate the mechanism of the vasodilatory effect induced by L-carnitine. Relaxation produced by L-carnitine was studied in rat aortic rings with and without functional endothelium, pre-contracted with phenylephrine by adding cumulative doses of L-carnitine (10(-7) to 10(-3) M). The relaxation evoked by L-carnitine reached higher values in aortic rings from spontaneously hypertensive rats than those obtained in arteries from normotensive rats; no relaxation was produced in de-endothelialized arteries. However, in the presence of N(G)-nitro-L-arginine (3 x 10(-5) M, a nitric oxide synthase inhibitor), Ro 68070 (10(-4) M, a thromboxane synthetase inhibitor-thromboxane A2/prostaglandin H2 receptor antagonist) or ICI 192605 (10(-5) M, a thromboxane A2 receptor antagonist) the relaxant response to L-carnitine was significantly inhibited. These results show that L-carnitine induced endothelium-dependent relaxation in the rat aorta and the mechanism of this relaxation appeared to be mostly mediated by endothelial production of nitric oxide but#10; also could involve prevention of the action of cyclooxygenase endothelial products acting on the thromboxane A2/prostaglandin H2 receptor.
这项工作的目的是研究左旋肉碱诱导血管舒张作用的机制。通过添加累积剂量的左旋肉碱（10⁻⁷至10⁻³ M），在预先用去氧肾上腺素预收缩的有功能和无功能内皮的大鼠主动脉环中研究左旋肉碱产生的舒张作用。左旋肉碱引起的舒张在自发性高血压大鼠的主动脉环中比在正常血压大鼠的动脉中达到更高的值；去内皮的动脉未产生舒张。然而，在存在N（G）-硝基-L-精氨酸（3×10⁻⁵ M，一种一氧化氮合酶抑制剂）、Ro 68070（10⁻⁴ M，一种血栓素合成酶抑制剂-血栓素A2/前列腺素H2受体拮抗剂）或ICI 192605（10⁻⁵ M，一种血栓素A2受体拮抗剂）的情况下，对左旋肉碱的舒张反应被显著抑制。这些结果表明，左旋肉碱在大鼠主动脉中诱导内皮依赖性舒张，这种舒张机制似乎主要由内皮产生的一氧化氮介导，但也可能涉及防止作用于血栓素A2/前列腺素H2受体的环氧化酶内皮产物的作用。
